1. Field of the Invention
The invention relates to a method of manufacturing a magnetic head slider including a thin film magnetic head device for recording or reproducing information on/from a recording medium such as a hard disk, and a method of fixing a bar for processing the magnetic head slider.
2. Description of the Related Art
In a magnetic recording apparatus such as a hard disk drive, a thin film magnetic head device for recording or reproducing magnetic information is mounted on a magnetic head slider facing a recording surface of a magnetic recording medium.
The magnetic head slider is manufactured through the following steps as proposed in Japanese Unexamined Patent Application Publication No. Hei 10-228617, for example.
First, many thin film magnetic head devices are formed by thin film process on a substrate (wafer) made of a ceramic material, for example. Subsequently, the wafer is cut into a plurality of bars, each of which includes at least one magnetic head slider, by using a dicing saw or the like. Surfaces of a plurality of bars thus obtained are polished, and then slider rails having a predetermined shape are formed on each surface by etching process using photolithography, or the like. Each bar having the slider rails is further cut into separate magnetic head sliders.
In the step of forming the slider rails, a bar surface opposite to a surface to be processed (i.e., the surface on which the slider rails are to be formed) is bonded and the bar is fixed directly onto a support substrate made of ceramics or the like.
However, a method in which the bar surface opposite to the surface to be processed is fixed directly to the support substrate as mentioned above has the following disadvantage. When the method is applied to a plurality of bars in a batch process, variations in thicknesses among the bars cause variations in heights of the surfaces to be processed among the bars (i.e., distances between the surface of the support substrate and the surfaces to be processed). Therefore, some bars are in exposure focus and others are out of exposure focus, when so-called full-wafer printing for simultaneously exposing a plurality of bars to light takes place in the process using photolithography, for example. The bars out of exposure focus exhibit variations in shapes of the slider rails, because a desired size or shape of a photoresist pattern to be used as a mask is not obtained. As a result, the method has a problem of having an influence on properties of the magnetic head slider (e.g., the amount of head levitation that corresponds to a clearance between the magnetic head slider and the recording medium, and so on).
Instead of full-wafer printing, so-called step-and-repeat exposure for exposing the bars one by one to light can take place in order to solve the above-mentioned problem. However, a problem exists: manufacturing costs increase because a stepper is expensive. Another problem exists: manufacturing takes a long time because the bars one by one are exposed to light.
A method in which a plurality of bars is fixed in such a manner that their surfaces to be processed are located along a predetermined reference plane is proposed in Japanese Unexamined Patent Application Publication No. Hei 8-315341. Specifically, the surfaces of a plurality of bars to be processed are once bonded to a common glass plate, and then low-melting metal is poured around a plurality of bars and is left to be solidified. After the glass plate is removed, the bars are held by the low-melting metal with their surfaces exposed. The method allows the surfaces to be processed of the bars to have the same height (or level).
However, it is difficult for the method described in Japanese Unexamined Patent Application Publication No. Hei 8-315341 to precisely position the bars in a plane parallel to the reference plane (i.e., the surface of the glass plate). Thus, full-wafer printing for exposing a plurality of bars to light by using a common resist pattern may cause misalignment between the resist pattern and the bars. It is therefore difficult to form the slider rails having a precise shape. To cut each bar, into separate magnetic head sliders, the low-melting metal around each bar must be cut together with each bar. Consequently, the method also has a problem that the longevity of a cutting blade or the like decreases.
A method in which a plurality of bars is fixed to the support substrate in such a manner that a plurality of bars one by one is aligned in the plane parallel to the surface of the support substrate is proposed in Japanese Unexamined Patent Application Publication No. Hei 6-236508. Specifically, the surfaces to be processed of the bars are sucked and lifted by a suction holder, the support substrate placed on an XYZ table is appropriately positioned relative to the bars, and then the surfaces opposite to the surfaces to be processed of the bars thereof are fixed to the support substrate. However, the method described in Japanese Unexamined Patent Application Publication No. Hei 6-236508 has the same problem as the problem of Japanese Unexamined Patent Application Publication No. Hei 10-228617, because the surfaces opposite to the surfaces to be processed are fixed directly to the support substrate. That is, variations in thicknesses of the bars cause variations in heights of the surfaces to be processed. As a result, the method has a problem of having difficulty in forming the slider rails having a precise shape in the process using photolithography, or the like.
The invention is designed to overcome the foregoing problems. It is an object of the invention to provide a method of manufacturing a magnetic head slider and a method of fixing a bar which can improve fabrication accuracy without increasing manufacturing costs.
According to the invention, a method of fixing a bar to a predetermined support member in order to process a predetermined surface of the bar that is a long member including at least one magnetic head slider comprises the steps of: arranging a plurality of bars with their surfaces to be processed along a predetermined reference plane; and moving and placing the plurality of bars onto the support member while maintaining the relative positions of the bars, wherein the arranging step includes positioning of each of the plurality of bars in a plane parallel to the reference plane.
In a method of fixing a bar of the invention, the surfaces of a plurality of bars to be processed are located along the reference plane. Thus, all the surfaces of a plurality of bars to be processed can be brought into exposure focus even if, for example, full-wafer printing takes place in a process using, for instance, photolithography. Therefore, a slider rail can be precisely formed. Moreover, each bar is positioned in the plane parallel to the reference plane. Thus, it is easy to align a resist pattern for, for example, photolithography with the bar. Therefore, the slider rail can be precisely formed. Moreover, there is no need for step-and-repeat exposure for exposing the bars one by one to light. Therefore, the manufacturing time is reduced, and an expensive stepper is not required and thus manufacturing costs are reduced.
Desirably, in the step of transferring, the plurality of bars is fixed to the support member with an adhesive between the surfaces opposite to the surfaces to be processed of the plurality of bars and the support member. Thus, the thickness of the adhesive can vary according to variations in thicknesses of a plurality of bars. Therefore, a plurality of bars can be held with their surfaces to be processed aligned with the reference plane.
Desirably, the arranging step includes the steps of: bringing the surfaces of the plurality of bars to be processed into direct contact with the reference plane by using a reference member having a surface for determining the reference plane; and holding the plurality of bars by the reference member. Thus, the surfaces of a plurality of bars to be processed can be aligned with the reference plane by a simple method.
Desirably, the step of transferring further includes the steps of: applying an adhesive to the support member; bringing the surfaces opposite to the surfaces to be processed of the plurality of bars held by the reference member into contact with the adhesive; and separating the reference member from the plurality of bars after the adhesive sets.
Desirably, in the arranging step, the plurality of bars is positioned relative to the reference plane concurrently with observation of a predetermined mark formed on each of the bars. Thus, each bar can be precisely, simply positioned.
A method of fixing a bar of the invention may include, prior to the arranging step, the step of forming a protective film on at least one surface of the bar except the surface thereof to be processed. Thus, for example, a thin film magnetic head device formed on any surface other than the surface of the bar to be processed can be protected from damage due to the process (e.g., etching for photolithography) or the like.
Desirably, the plurality of bars includes a plurality of types of bars having different lengths. Thus, the bars can be cut from a wafer without wasting the bars, and therefore materials can be saved.
A method of manufacturing a magnetic head slider of the invention comprises the steps of: forming thin film magnetic head devices on a predetermined base; cutting the base into a plurality of bars, each of which includes at least one magnetic head slider on which the thin film magnetic head device is formed; arranging the plurality of bars with their predetermined surfaces along a predetermined reference plane; moving and placing the plurality of bars onto a predetermined support member while maintaining the relative positions of the bars, thereby supporting the plurality of bars by the support member; applying a predetermined process to the plurality of bars supported by the support member; and separating the bars into separate magnetic head sliders by cutting the bars, wherein the arranging step includes positioning of each of the plurality of bars in a plane parallel to the reference plane.
In a method of manufacturing a magnetic head slider of the invention, predetermined surfaces of a plurality of bars, i.e., the surfaces to be processed are located along the reference plane. Thus, all the surfaces of a plurality of bars to be processed can be brought into exposure focus even if, for example, full-wafer printing takes place in, for instance, photolithography. Therefore, the slider rail can be precisely formed. Moreover, each bar is positioned in the plane parallel to the reference plane. Thus, it is easy to align a resist pattern for, for example, full-wafer printing with the bar. Therefore, the slider rail can be precisely formed. Moreover, there is no need for step-and-repeat exposure for exposing the bars one by one to light. Therefore, the manufacturing time is reduced, and an expensive stepper is not required and thus manufacturing costs are reduced.
Other and further objects, features and advantages of the invention will appear more fully from the following description.